The present invention relates to a vehicle driving force control device controlling a driving force of a vehicle.
In an engine automatic transmission vehicle (hereinafter, referred to as an engine AT vehicle), even though an accelerator pedal is not operated, the vehicle can be slowly started (a creep phenomenon). Even in an electrically-driven vehicle such as an electric vehicle or a hybrid vehicle, the same control is performed. That is, even though the accelerator pedal is not operated, excitation current of a driving motor is controlled to control a creep torque, such that the vehicle can be slowly started.
In a brake apparatus of a vehicle, a negative pressure type or a positive pressure type boosting device is provided assisting a force (a stepping force) for stepping a brake pedal, and a pressure of a brake fluid (hereinafter, referred to as a brake fluid pressure) is increased by using the boosting device to increase the brake force. However, when a pressure generating device supplying negative pressure or positive pressure is faulty, a pressure cannot be supplied to the boosting device. In such case, even though a driver's stepping force is the same, the brake fluid pressure is reduced as much as the assisting force by the boosting device is removed. When the creep torque is controlled (reduced) by a value of the brake fluid pressure, it is difficult to reduce the creep torque, and as a result, a driver may feel as if a vehicle is pushed out and feel a sense of incompatibility.
In JP-2004-282903A, the creep torque generated in a motor is determined according to a stroke amount of the brake pedal, but it is not distinguished whether the brake apparatus is normal or abnormal, and as a result, even when the brake force is reduced or is abnormal, the creep torque is controlled in the same manner as it is controlled when the brake apparatus is normal, such that the driver may feel as if the vehicle is pushed out and feel the sense of incompatibility.
Meanwhile, in JP-2010-075036A, when a brake is faulty, the creep torque is reduced depending on a vehicle velocity, but relevance to the brake pedal is not described and the driver may feel the sense of incompatibility.